This invention relates generally to can openers and more specifically to power operated can openers of the type which remain on during shearing of a can lid and which shut off automatically on completion of the can shearing.
This type of can opener has proven to have significant practical advantages, particularly in reducing the inconvenience to the user. However, for the most part, existing can openers of this type are complex and expensive to construct, and the shut off mechanisms do not operate reliably, especially after prolonged usage. In addition, the switches employed in the prior art can openers are not altogether effective in achieving power pierce of the can lid as easily as possible.
The present invention is also concerned with an improved latching mechanism which pivotally mounts the hand lever on the frame while at the same time permitting easy removal of the lever for cleaning and other purposes. A can opener with a latching mechanism that releases upon movement of the hand lever to a position beyond its normal pivot arc is disclosed in U.S. Pat. No. 3,688,400. This type of latch has proven relatively successful on the whole, although problems sometimes develop due to lever wobble as it is pivoted. This wobble occurs because the latch plate is located rearwardly of the hand lever in a plane offset from that of the lever, thereby enabling the latch plate to move relative to the lever.
The subject invention further contemplates the provision of an electrically powered can opener which may be driven manually in situations where an electrical outlet is unavailable. Conventional electric can openers operate only by means of electrical power and are incapable of opening cans unless an electrical power source is available. In the present invention, this drawback is eliminated because the can opener is able to be operated by a manual crank as an alternative to being electrically driven.
It is an object of this invention to provide a power operated can opener which includes a simple, effective and economical means for maintaining the motor in its energized condition as a can lid is being sheared and for automatically deenergizing the motor when the can shearing has been completed.
Another object of the invention is to provide a can opener of the character described which utilizes the operating thrust to maintain the motor energized during shearing of a can end. Accordingly, automatic shut off is effected when the can shearing is completed and the operating thrust is no longer present.
In conjunction with the preceding object, a still further object of the invention is to provide, in a can opener of the character described, a cutter mounting plate which is able to slide relative to the hand lever in order to effect automatic shut off of the motor. The cutter mounting plate includes a tab projection which engages a catch on the frame with greater lateral force than upward force during can shearing to retain the lever against the motor switch. However, after completion of the can shearing, the upward force is greater than the lateral force and the cutter mounting plate is able to slide in order to release the tab from the catch and thereby deenergize the motor.
A further object of the invention is to provide a can opener of the character described in which a camming surface is formed on the catch in order to properly position the tab projection relative thereto.
Still another object of the invention is to provide a can opener of the character described which includes an improved rotary type switch for energizing and deenergizing the motor, the switch achieving easier power pierce of a can lid as compared to switches heretofore used in can openers.
An additional object of the invention is to provide a can opener having a simple and reliable latching mechanism which retains the hand lever on the can opener frame and yet permits quick and easy removal of the lever therefrom. Any tendency of the lever to wobble as it is pivoted on the frame is eliminated due to the engagement of a portion of the hand lever itself by the latch.
Yet another object of the invention is to provide a can opener which may be driven either with electrical power or with a manual crank.
A still further object of the invention is to provide, in a can opener of the type described in the preceding object, means for disengaging the motor from the drive train when the crank is employed and for returning same to the drive train when the crank is removed.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.